Vacuum device



June 18, 1935. R. F. GOWEN El AL VACUUM DEVICE 2 Sheets-Sheet 1 FiledApril 5, 1918 K J a r j 0 0 m 4 A 1 W .L m T a, mu m w 6 MW M W ff Jv aM wk;

June 18, 1935. GQWEN 2,005,419

VACUUM .DfivIcE 2 Sheets-Sheet 2 Filed April 3, 1918 J v m a rwa /07" MPatentedlune 18, 1935 g i i .UNITED .STATESjPATENTOFFlCE 2,005,419VACUUM DEVICE Robert F. Gowen, Ossining, N. Y., and James L. Bradford,Elizabeth, N. J., assignors, by mesne assignments, to Radio Corporationof America, a corporation of Delaware Application April-3, 1918, SerialNo. 226,537 7 Claims. (01. 250-215) g This invention relates to vacuumdevices, and Fig. 12 is a bottom pl n Vi w Of h Construcmoreparticularly to devices of this nature used tion shown in Fig. 10. forthe purpose of detectors, amplifiers, and os- The same part isdesignated by the same refercillation generators, such as are in use inradio ence character wherever it occurs throughout the communicationwork, and commonly known as several views.

audions. Our present invention is directed to a compact, The object ofthe invention is to provide a denovel and efficient arrangement ofelements in vice of the character described which is simple vacuousvessels or tubes known as audions, and

in structure, efiicient in operation, and economiwhile the same isparticularly adapted for use as v cal of manufacture. an audion, andalthough for the purpose of illus- 10 A further object of the inventionis to provide tration, we will hereinafter refer to the same a device ofthe character described which is as an audion, we wish it to beunderstood that the rigid, stable, small and compact, and which willinvention is not to be limited or restricted in this afford long lifewith hard usage. respect.

A further object of the invention is to pro- In wire or wirelesscommunication work where 5 vide a new and improved grid electrode fordea detector, amplifier or oscillation generator, vices of thischaracter. known as the oscillion, is required, or is used, it A furtherobject of the invention is to prois greatly to be desired to have a.device which vide a new and improved mounting for the grid, is simple instructure, efiicient in operation, and

filament and plate electrodes used in devices of economical ofmanufacture, in addition towhich 20 this char cter. compactness,rigidity and strength is a requisite.

Furthe mbjects of the invention will appear Due to the characteristicsof the device, the same more fully hereinafter. being an evacuatedvessel, usually and preferably The invention consists substantially inthe conof glass, the advantages of a compact, rigid, strong struction,combination, location, and relative arunit are apparent. 25 rangement ofparts, all as will be more fully In accordance with our invention weprovide hereinafter set forth, as shown by the accomwhat we will termthe base indicated generally panying drawings, and finally pointed outin at I blown from glass in the usual manner, which the appended claims.is in the form of a hollowed stem, having anchored Referring to thedrawings: therein the supports 2 for the plate electrode, sup- 30 Fig. 1is a view in elevation of an electrode ports 3 for the grid electrode,and supports 4 for base employed in accordance with our inventhefilament electrode. Connected to the 'filation. ment supports 4 are thefilament leads 5 and 6 Fig. 2 is a similar view showing the filamentrespectively, and connected to one or more of the electrode appliedthereon and placed under tengrid supports 3 is the grid lead 7, andconnected 35 sion. to one or more of the plate supports 2 is the Fig. 3is a similar view of the grid electrode plate'lead 8. The respectiveleads to the grid,

ready for application. plate and filament electrodes extend through theFig. 4 is a top plan view of the same. base I down through the hollowedor stem portion Fig. 5 is a view of a section of material from thereofas clearly shown. Also anchored in the 40 which the grid electrode ismade prior to bebase I is a forked support 9, that is, a support ingplaced in condition for use. extending vertically upward and providedwith a Fig. 6 is an enlarged detail view in horizontal forked end. Thefilament electrode I0 is suitably section of one side of a grid winding.secured, as for example, welded to ,the supports Fig. 7 is a view inside elevation of same. which are bent outwardly away from each other 45Fig. 8 is a view similar to Figs. 1 and-2 showing in the form of aspring and the filament extends the grid electrode mounted and inposition. from one support to the other over the forked Fig. 9 is a viewin partial vertical section of end of the vertical support 9. Thevertical supan assembled. device viewing the plate electrode port 9, itwill be noted as shown in Fig. 1, i

in side elevation. vided with an irregularity or bend in the body 50Fig. 10 is a similar view, viewing the plate thereof. The purpose ofthis bend is to insure a electrode in central longitudinal section.proper tautness of the filament it. The; filament Fig. 11 is a sectionalview taken on the line II, In is usually and preferably of tungsten, andas H, Fig. 9, and looking in the direction of the same is provided withcurrent to heat the samein 5 arrows. its use, becoming heated and cooledrepeatedly causes the same to expand. It is necessary in maintaining theefficiency of the device to maintain the filament I 0 taut. Thus it willbe seen that after the filament has been welded to its supports 4 whenthe vertical forked support 9 isstraightened into the position shown inFig. 2 the filament Ill is stretched into a taut position imposing astrain on the spring supports 4, which spring supports 4 thereaftermaintain the filament ID in a taut condition under all conditions ofoperation, either when the electrode is cold or expanded when heated. Asabove explained, the grid electrode comprising the parts I2, I3 and I4is mounted on the supports 3 in any suitable manner, for example, bybeing welded thereto.

We will now describe the method of construction of the grid, themounting thereof, and its ultimate position shown relative to thefilament. The grid electrode comprises two supporting members I2 and I 3of small diameter metal, about which is wound spirally at a constantpitch a wire I4. The wire I4 is welded to each of the supports I2 and I3on the exterior portion thereof as indicated at I5, Fig. 6. In Fig. 5 weshow a strip from which the grid electrode is made in which the wire I4has been wound around the supports I2 and I3 and welded thereto as aboveexplained. We find that it is advantageous to maintain the coils of thewire I4 in a taut condition and equally spaced relative to each other inall positions, therefore we have found that by depressing the wires onone face of the strip in one direction as indicated at I5 and the wireson the other face of the strip in the opposite direction thespace,between the respective coils remains constant and all slack in thewire between weldedpoints is thus eliminated. It is necessary tomaintain the opposite faces I6 and ll of the grid electrode in a planeparallel to the plane in which is located the filament electrode. Wehave also found that greater efliciency 'of the device is secured byspacing the coils one-sixteenth of an inch apart, within which space islocated the filament electrode. We also find that a space betweenwindings of the grid electrode of onesixteenth of an inch enhances theefliciency of the audion. We also find that a grid wire of diameter of.008 inch is preferable to use, the

grid supports I2 and I3 being located .030 inch apart. Although a greatnumber of tests and experiments extending over a period of considerabletime has resulted in our adoption of the foregoing specifications as thepreferable form, we do not desire to be limited or restricted to thesedetails. We have found it advisable and preferable to use enough gridwire to completely cover the filament electrode. In the foregoingexample we have found that a grid electrode comprising nine coils ofwire to be the most efiective. After the audion base has beenconstructed as shown in Fig. 2 the grid electrode shown in Fig. 3 isthen mounted on its supports 3 and suitably secured thereto, forexample, by being welded thereto, with the filament electrode positionedbetween the opposing faces I6 and I! of the grid electrode and with thefaces I8, I1, and the filament I0, all located in parallel planes withthe filament I0 an equal distance between the opposed faces of the gridwires. The plate electrode I8 comprising preferably a single sheet ofnickel of suflicient width to completely enclose the grid electrode andsuillcient height to pass over the same rectangularly as clearly shownin Figs. 9 and 10 is suitably secured, for example,

by being welded, to the plate supports 2. The

plate electrode I8 comprises the two side members and a-top with acentral opening stamped out of the top, which side members are bent downinto planes parallel with the plane of the grid electrode and thefilament electrode and spaced an equal distance from its cooperatingside of the grid electrode. The device thus far constructed is thenenclosed in preferably 'a glass vessel I9, which vessel is thereuponsealed to the base I and evacuated to the proper degree of evacuationrequired in devices of this nature, and is then sealed off leaving acompleted compact audion structure of exceeding strength and rigidityand remarkable efiiciency, with all of the leads of the electrodesextending out of the saine at one point, namely, through the hollow stemportion of the base I, as clearly shown in Fig. 9.

We will now describe the mounting of the audion which permits of addedstrength and affords to a great extent a protection against the glassvessel IQ of the device becoming broken. The audion vessel I 9 isinserted in a receptacle 20 of any suitable construction, preferably ofmetal, as shown in Fig. 9, and is anchored therein in any suitablemanner, preferably by means of an insulating adhesive compound indicatedat 2I. It will be noted that the body of the vessel I9 is substantiallyenclosed in the receptacle 20 thereby strengthening the same, and due tothe width of the receptacle 20 in case the device falls into ahorizontal position the glass bulb portion thereof is not subjected-toshock on impact. The respective leads of the electrodes extend down intothe receptacle 2!! from the hollow stem portion of the base I and may beinsulated from each other in any desired manner, for example, by meansof sleeves 22. A cap or cover 23 is inserted in the open end of thereceptacle 20 which cap or cover may be of any suitable construction ormaterial. We find it preferable, however, to make the cap or cover 23 ofa non-conductive waterproof material, and to coat the edges thereof witha suitable cement or adhesive to effectively seal the interior of thereceptacle 2!] when the cap or cover is placed on the same. The cap orcover is provided with four terminals 24 in which the wire leads of theelectrodes are located and anchored therein in any suitable manner, forexample, by being soldered therein as indicated at 25. In the use of theaudions it is preferable to ground one terminal of the filamentelectrode and preferably the positive terminal. We provide a simplemeans for accomplishing this wherein the wire 26 is suitably secured tothe receptacle 20 inany desired manner, for example, by being solderedtherein. This wire 26 is then secured to the wire lead as indicated inFig. 9. Thus it will be seen that we have provided an audionconstruction wherein all of the electrodes are provided with leads atone point, namely, the base of the audion terminating in four rigidposts 24, one post being connected to the grid electrode, one to theplate electrode, and two to the filament electrode. This permits the useof a standard socket receptacle for the audion bulb whereby all that isnecessary to place the audion in circuit is to place the audion unitinto its receptacle thus eliminating making connections by hand andestablishing wire leads from various points of the bulb. It may bedesired to insure a proper insertion of the audion bulb in its socketand to provide means for retaining the audion bulb in its socket. Forthis purpose we show at a projection on the receptacle 20, whichprojection may cooperate with a groove in the receptacle orsocket toform in effect a bayonet lock and at the same time insure properdisposition of the various electrodes of the audion unit.

Many modifications will occur to those skilled in the art withoutdeparting from the broad spirit and scope of our invention, as definedin the claims, therefore, what we claim as new and useful, and of ourown invention, and desire to secure by Letters Patent, is:

1. A vacuum device comprising a filament and grid electrode, a plateelectrode comprising a single piece of metal with a central opening cuttherethrough and bent downwardly on opposite sides of said centralopening.

2. A vacuum tube comprising a press, a. cathode, a helical gridsurrounding said cathode, an anode surrounding said grid, and metallicmeans connecting said electrodes and said press and forming the solesupport for said electrodes.

3. An audion mount comprising a base with a press portion, a pair ofmetallic spring supporting arms sealed into said press, a filamentattached at opposite ends to said arms, another supporting arm sealedinto said press intermediate the first mentioned support arms andadapted to engage the filament intermediate its ends to maintain ittaut.

4. An audion mount according to claim 3 in which said other supportingarm has a looped portion intermediate its ends.

5. An electron discharge tube comprising a stem having a press, aplurality of pairs of metallic supports embedded in said press, andcooperating electrodes mounted on said stem and comprising a filamentarycathode secured to and carried by one pair of said supports, a gridcomprising a pair of independent metal rods mounted parallel to eachother on opposite sides of said cathode with their ends joined toanother pair of supports and a continuous wire wound around said rodsinto a flattened helix coaxial with and surrounding said cathode andhaving each turn secured to said rods and an anode supports constitutingboth the electrical connections and the sole supporting means for saidelectrodes.

6. An electron discharge tube comprising a stem having a press, acathode electrode, a grid electrode coaxial with said stem andsurrounding said cathode and comprising a pair of metal rods mounted atone end on said press and projecting side by side and independent ofeach other from said press on opposite sides of said cathode and a wirewound around said rods forming a continuous helix surrounding saidcathode with each turn secured to said rods, an oblong anode electrodeof sheet metal coaxial with and surrounding said grid and open at bothends and having two sheet metal side portions disposed onoppositesidesof said grid and parallel to the plane of said rods, eachof said portions being wider than said grid and of a height as great asthe length of said grid, and metal wires sealed into said press andconnecting said electrodes and said press and constituting the solesupports for said electrodes.

7. An electron discharge device comprising a press, a cathode on saidpress, an oblong anode coaxial with and surrounding said cathode, and agrid electrode on said press comprising two parallel side rods mountedat one end on said press and projecting from said press with their otherends free, said side rods being held spaced from each other solely bysaid press, and a grid wire wound over said rods into a. continuoushelix of substantially the length of said Beds with each turn of saidhelix joined to said rods and surrounding said cathode, therebyinterposing between said cathode and said anode intermediate said twoside rods only those portions of said grid electrode which consistsolely of turns of grid wire.

ROBERT F. GOWEN. JAMES L. BRADFORD.

